About Variable Selections

You can define selections and tags using annotations.

You can put the annotations in the actual model, but you can also put them in separate models, enabling reusability.

You can use variable selections to control display and storage of variables.

You can create a number of selections, using a graphical user interface or writing code. For details of the graphical user interface, see Creating and Editing Variable Selections.

You can include selection annotations in several models, not only on the top level. The override attribute in the Selection constructor (see below) determines if selections with the same name found on lower hierarchical levels of the model should be overridden or merged.

By default, if a model has any variable selections, variables not present in any variable selection are not stored in the result file; resulting in a decrease of file size, valuable for large models. Such nonselected variables are considered protected, which means that the setting to store protected variables can be applied if you want to also store nonselected variables in the result file when having selections. For more about the Output tab, see Simulation Setup Dialog Box.

When simulating, you can select what selections to display, by commands in a panel in the Variable Browser. See Displaying Variable Selections in the Variable Browser.

You can use variable selections to create variable lists for plotting. See Variable Selections for Plotting.

The annotation for selection is:

annotation(__Dymola_selections={Selection(...),...})

where the selection constructor is:

record Selection
   parameter String name;
   parameter Boolean override=false;
   parameter MatchVariable match[:]=fill(MatchVariable(),0);
end Selection;

and the matching constructor is:

record MatchVariable
   parameter String className="" "Regular expression for classes to look in";
   parameter String name="*" "Regular expression for variable name";
   parameter String description="" "If non-empty, regular expressions that should exactly match description";
   parameter String tag[:]=fill("",0) "If non-empty, regular expressions that should exactly match any tag";
   parameter String newName="" "For storing under different name";
end MatchVariable;

The annotation for tags is:

annotation(__Dymola_tag={"Tag2","Tag3"});

If a tag is attached to a component, it is also attached to subcomponents and variables.

Matching can then be made on tags as well.

Variables can be tagged using the tag annotation:

Real w annotation(__Dymola_tag={"Mechanical"});

Several tags can be associated with a variable:

Real w annotation(__Dymola_tag={"Mechanical","Rotational"});

As an example, consider the below model where two selections have been defined:

model Selection4
  annotation (__Dymola_selections={Selection(
        name="Angles",
        override=true,
        match={MatchVariable(name="*.phi")}),Selection(
        name="Torque",
        override=true,
        match={MatchVariable(name="*.tau")})});
end Selection4;

This corresponds to the following items in the advanced filter dialog box in the Variable Browser:

• Parameters and States
• Angles
• Torques

The selection Parameters and States is predefined corresponding to the interactive fields for setting parameters and initial conditions of states.

As an example, consider Example 1 above, but to create a new section in the Variable Browser with the same variable name as already selected, you can use newName="%componentPath%%name%" or alternatively newName="%path%". Using the former alternative gives:

model Selection5
  annotation (__Dymola_selections={Selection(
        name="MySelection",
        override=true,
        match={MatchVariable(name="*.phi", newName="%componentPath%%name%")})});
end Selection5;

This gives the same result in the Variable Browser as Example 1 above, but also the following additional content:

To build subtrees, you can include the subtree name in the newName path. As example, extending Example 2a above with newName parameters:

model Selection6
  annotation (__Dymola_selections={Selection(
        name="MySelection",
        override=true,
        match={MatchVariable(name="*.phi", newName="Angles.%componentPath%%name%"),
          MatchVariable(name="*.tau", newName="Torques.%componentPath%%name%")})});
end Selection6;

This gives the same result in the Variable Browser as Example 2a above, but also the following additional content: